Details of the
development of radio equipment
for ionospheric research are
well documented and it was as a
result of this early work that
it was realised the techniques
developed could also be used for
the detection of transmissions
reflected from objects below the
level of the atmospheric levels
being studied. This resulted in
the use similar equipment for
measuring the range of aircraft
or shipping, as well as for land
masses.

The
value of these capabilities was
recognised in many countries
including the UK, Germany and
the USA which resulted in
further research to produce
prototype outfits for military
use. Initial work in UK
concentrated on the provision of
radio equipment for determining
the range and direction of
aircraft to improve defence
against air attack and later for
use in controlling anti-aircraft
weapons both on warships and
ashore. In order to preserve the
secret nature of this work in
the UK it was designated as being RDF or Radiolocation,.
However in 1942 this type of
equipment became known as Radar
in the RN and USN.

New Zealand scientists
had been involved in research
work associated with use of
radio equipment for the
investigation changes in
atmospheric and weather
conditions since Ernest
Rutherford arrived in Cambridge
in 1895. He had already carried
out radio research in New Zealand and
initially continued to
investigate the propagation of
electromagnetic waves before
moving on to nuclear physics.
Nevertheless he was aware of the
development activities at Bawdsey
which lead to the establishment
of an aircraft warning system
(CH). This was the first
national defence radar system of
this type and was in operational
use by early 1939. His
prominence in scientific
activities in UK enabled
Rutherford to arrange for loan
of equipment to assist in
research being undertaken in New
Zealand universities. More
importantly he encouraged the
recruitment of graduates from
New Zealand to the UK
to join research teams concerned
with radio research.

Corrections
with thanks to Dr John A
Campbell, Physics Dept,
University of Canterbury,
Christchurch New Zealand.

Author
of Rutherford Scientist
Supreme, Rutherford's
Ancestors

A
correction is needed to the
third paragraph, which currently
reads at the start.

"New Zealand scientists had been
involved in research work
associated with use of radio
equipment for the investigation
changes in atmospheric and
weather conditions since Edward
Rutherford arrived in Cambridge
in 1895. to investigate the
propagation of electromagnetic
waves before moving on to
nuclear physics."

(a) "He had already carried out
radio research in NZ " No he
hadn't. He had developed the
magnetic detector of fast
current pulses (later modified
to become the Rutherford/Marconi
magnetic detector) and had taken
that to England where he used it
to detect wireless waves.

Rutherford in NZ did study the
high frequency waves traveling
along a wire but didn't separate
his damped, short, current pulse
generator (initially Leiden Jar
discharges, later a Hertzian
oscillator) from his detector
circuit until he went to
Cambridge and started
experiments using Hertzian
wavesto determine the
comparative sensitivity of his
magnetic detector of short
current pulses and in so doing
established a record for the
distance over which wireless
waves were detected.

To use the terms "radio" and
"continued" in the current entry
are both misleading and should
either be altered or a fuller
explanation given. My suggestion
would be to replace:-

"He had already carried out
radio research in New Zealand
and initially continued"

with

"In New Zealand he had developed
his magnetic detector of fast
current pulses and took his
detector to Cambridge where, in
1896, he set the record for the
distance over which wireless
waves were detected. His device
was later modified to be the
Rutherford-Marconi magnetic
detector of wireless signals."

I wouldn't like for NZ to be
accused of claiming more than
its dues.

However, if wished, the entry
could also include something
like:- After World War I,
Rutherford as director of the
Cavendish Laboratory, encouraged
radio research, including that
of Appleton who received a Nobel
Prize for measuring the altitude
of the ionosphere."

One
of these was Ernest Marsden
who joined the Cavendish
Laboratory in Cambridge to work
on radio propagation and later
became Director of Scientific
Development which had been
established to support radio
research in New Zealand and had been provided with funding by the Committee of Imperial
Defence in London.
The basic overall philosophy in
1939 was that technical details
of the developments in radar
were to be shared by New Zealand
as well as with the other three
major dominions of the British
Empire. These countries were
asked to send a physicist to
study the current state of radio
research and radar equipment
being developed in UK so as to
assist in the introduction and
use of radar for their own
defence. Dr Marsden
was selected to represent New Zealand.

....and

Marsden
wasn't an NZ graduate, he went
to NZ after graduating from
Manchester.

"One of these was Ernest
Marsden who joined the
Cavendish Laboratory in
Cambridge to work on radio
propagation and later"

I would suggest changing that
to

"Ernest Marsden who, as an
undergraduate at Manchester,
had made the large-angle,
alpha-scattering experiments
for Rutherford which the
latter used to show that atoms
had a nuclear structure,
later"

He
arrived in England during April
1939 and visited Bawdsey
and other establishment involved
in radar development. As a
result he was able to easily
absorb the fundamentals and
techniques associated with
entire new type of equipment and
before his return had been able
to arrange for future supply to
New Zealand of technical data,
procedures and also for supply
of components essential for
production of radar equipment.
He also obtained vital items of
hardware which were not
available locally. These
included co-axial cable,
oscilloscopes and two television
receivers, from the design of
which radar receiving units had
been developed in UK. In
addition he also brought
components of the newly
available radar fitted in RAF
aircraft (Air-Surface vessel
(ASV) Mk 1) for use in New
Zealand.

His primary
objectives were to design and
manufacture radar equipment
needed for warning of the
approach of aircraft and ships
to be fitted in warships and
ashore, as well as fire-control
radar equipment which could be
use on ships or on shore. Two
highly secret teams were then
set up, one in Christchurch to
develop equipment for shipboard
use and the second at Wellington
to develop to develop a fire
control equipment for shore
defence against ship attack and
also a radar suitable for use in
aircraft.

Despite the
enormous difficulties caused by
lack of suitable scientific
staff and inadequate up-to-date
publications needed to
understand the new scientific
techniques being used amazing
progress was made. One of the
difficulties encounter was that
needs of meeting priorities took
precedence over the equally
important requirement to
organise the work in a way which
would avoid duplication of
effort available.

After
the development of suitable
equipment designed to operate on
microwave frequencies, made
possible by the use of magnetron
valves, Dr Marsden
visited UK again early in 1941
and before return to New Zealand
also visited the USA and Canada.
During his absence many the
basic radar programme
had been re-organised but he was
able to take steps to ensure
that he remained responsible for
organising all aspects of
research, development and
production of radar equipment in
New Zealand.
An offer to supply New Zealand
radar to RN ships in Singapore
was made but the numbers offered
proved over optimistic and in
any case the fewer fire control
sets completed were never
delivered, and one may have been
taken from the NZ mercantile
HAURAKI during passage to Ceylon
in the Indian Ocean on 12th July
1942 where it was intercepted by
a Japanese surface raider.

1
9 3 9 t o 1
9 4 3

HMNZS Achilles
(NP, click for enlargement)

After
the outbreak of war with Japan the reliance
placed by New Zealand that
imperial support from London
would always be available was
reduced and arrangements had
been made to obtain to obtain
advice and support from the USA
together with components
required for production of
microwave radar equipment. As a
result it is clear that most
radar equipment manufactured in
New Zealand was microwave
equipment, especially equipment
required for shore use for
aircraft or ship warning and
capable of transport to isolated
positions in the Pacific Ocean.
After 1943 little radar
equipment was produced in New
Zealand and RNZN warships were
then provided with British
outfits to replace the earlier
New Zealand
sets.

The
first radar equipment produced
in New Zealand was not
identified by using those used
by the RN or the USN although
those used are similar enough to
recognise. However in the case
of Air-Surface Vessel radar
(ASV) fitted in aircraft there
were two types, Mk1 and Mk2
which used different
frequencies. The first NZ
prototype equipments some
components obtained from UK in
1939 and used a transmitter
frequency of 45 MHz and later
types were designed using
frequencies about 200MHz similar
to equipment developed in UK. A
Homing Beacon for use with ASV
radar sets was produced in New Zealand.
UK ASV Mk2 was later solely used
by the RNZAF

The British ASV
radar used in RAF aircraft was
fitted in the WALRUS aircraft
carried on board HMS ACHILLES.
A second
radar of this type was fitted
for use on board with a modified
aerial unit to suit this use.
Further details are required
about this type of installation.
The modified ship variant was
also fitted later in HMS LEANDER
and a production model installed
in HMS MONOWAI.

All
radar designed in New Zealand
before 1942 used a frequency
below 500M/c as insufficient
information and no suitable
hardware was obtainable until
details of microwave technology
and information could be
provided. Some difficulties were
experience in obtaining
compatible components locally
was experienced and other items
were dependant on supply from UK
or elsewhere. No mass Production
facilities were available

HM Cruiser
ACHILLES was the first Royal
Navy cruiser to be fitted with
fire control radar, identified
as SS1, in July 1940. The first
trials of this type of equipment
were not carried out on the
British equivalent until
November that year. It is clear
that New Zealand design
equipment for surface defence
was in operational use before
1941 and that some design
techniques such as use of rack
fitting instead of cabinets with
inferior access to wiring and
components were developed and in
use much earlier than in RN
equipment.

NEW
ZEALAND
RADAR EQUIPMENT

HMNZS
Leander (NP/Mark Teadham, click
for enlargement)

SS
Type Radar (Later SWG)

Unlike the
British Types 285 and 284 radars
which used a wavelength of 50cm,
the first model fitted in HMS
ACHILLES used a wavelength of
66cm and the later model fitted
in August 1942 (SS1) used 73cm
wavelength. The aerial unit,
mounted on the 6 armament
Gunnery Director was made up of
two dipoles, one for
transmission and the other for
reception. and
were mounted in single
cylindrical paraboloid
reflector. The 5kw transmitter
was a pair of self squegging
VT90 oscillators with pulse
output at 2000cps, which
replaced a lower power design The
receiver was a super-heterodyne
with a line tuned mixer feeding
a 45m/c IF Amplifier from a PYE
television receiver. A 4 CRT
was used to display a 30.000 yd.
time base with calibration
markers at 1,000
yards. A prototype model was
also fitted in HM Armed Merchant
Cruiser MONOWAI.

In
August 1941 this model was
replaced by a modified design
(SS1) which was fitted to HMS
ACHILLES and HM Cruiser LEANDER.
These two ships were transferred
to the RNZN when the RN New
Zealand Division of the RN was
replaced. The modified version
had a wavelength of 73 cm and
greater transmitter power output
was available using HF110
valves. A new design aerial unit
mounted within a paraboloid
reflector sited on the 6
armament director including had
two Yagi
design elements, each having 13
additional dipoles acting as
directors and one folded dipole
radiator. This change gave
better bearing accuracy and
detection at a greater range.
Improved display facilities were
available, a local indicator
using an elliptical display to
provide either a slow time base
for normal use, or a fast time
base for accurate ranging.
Another 5 CRT was used to
assist in training of the
director presumably mounted in
the director. Another set of the
modified version was fitted in
the HMZNS MONOWAI being used as
an AMC before conversion to an LSI(L)
during 1943. Another fitting in
HM Cruiser CANBERRA
(RAN) is to be confirmed.

SWG
Type Radar

This
equipment was based on the
modified Type SS1 and used a
slightly longer wavelength with
a two different design aerial
units available.
The ship borne version was
similar to that used Type SS1
and was mounted on the gunnery
director. The alternative
framework aerial was mounted on
a Pylon and had four Yagi
type arranged in pairs, the
upper being used for
transmission and the lower pair
for reception. Each Yagi
had a folded dipole radiator and
eight director dipoles with an
associated trigonal
reflector. Fit of this improved
design in both cruisers is to be
confirmed but this is possible
as both ships were deployed
based at Auckland
in late 1942. Eight of this Type
were
delivered for RNZN use. How the
aerials were sited is difficult
to determine!

A
Type
Radar

A
prototype
equipment for provision of
warning of aircraft or surface
approach was produced in 1940
using components and techniques
provided from UK.
The design was similar to that
used for the RN Type 286M but
used a much larger aerial unit
of Yagi
design. A modified aerial unit
was designed locally for ship
fits as the aircraft design was
not suitable in for ship fits.
This unit comprised two elements
one for transmission with a
folded dipole and the receiving
unit with a reflector. Each type
had either three or five dipole
units. Transmission of two
microsecond 7 KW pulses was
provided by a squegging
oscillator at a repetition rate
between 800 and 1200 cycles per
second. A super-heterodyne
receiver with a 4 M/cs
bandwidth was used and an A type
Display was provided with
calibration markers.

Land
Based Radar.

This type of
radar was given 2nd Priority for
development and two types were introduced.,
one for coastal watching to give
warning of the approach of
shipping (CWS) and another for
fire-control of shore batteries
sited for defence against
seaborne attacks. Both types
utilised techniques based use of
metric wavelength and were
similar to the ship fitted
equipment. These shore radars
both used stack Broadside aerial
arrays were made transportable
with their own power supplies.

CWS
Type Radar

The first
operational outfit fitted in a
manually rotated hut used a 200
M/c transmitter using a squegging
oscillator to provide two
microsecond pulses with a
repetition rate of 1,500 c/s at
power of about 7 KW. The
super-heterodyne receiver outfit
had an IF frequency of 45 M/cs
and a 15cm CRT provided an A
Type Display outfit to show
received signals out to over 30
miles or more if site was at a
higher elevation. The aerial
outfit was rotated by hand and
initially mounted on the side of
the hut. It comprised four
stacks of dipoles, the centre
two being used for transmission
and the outer stacks for
reception. A wire netting
reflector was used behind the
dipole units. In later models
the Aerial was separately
mounted and driven by coaxial
cable. Both variants were
subject to difficulties in
rotation in strong winds. These
outfits were used until 1943/44
when microwave radar became
available.

CD
Type Radar

The equipment
initially used for fire control
of shore batteries was identical
with the CWS except that two
manually rotated huts were used,
each with the same design four
element aerial unit
and a 30cm CRT used for display
of received beam switched
signals. Synchronisation of
rotation was totally de[pendent
on telephone communication
between the two operators! Range
of detection was again dependant
on height of the site.

Later variants
incorporated many improvements
including coaxial resonator
tuning of the RF and Local
Oscillator stages on the
receiver, use of a single five
stack aerial unit mounted on
only one hut, and improved
display of received signals. The
aerial consisted of 40 dipole
units, the centre three used for
transmission and the two outer
for reception.
A wire netting reflector was
used as in the four stack design,
Three displays were available in
the improved variant: a 12 CRT
for general observation, a 5
CRT to provide an accurate
presentation of a 3,000 yard
portion and a 5 CRT to provide
bearing data. The beam switched
signal from
the two receiving aerials were
shown side by side and when of
equal height equal indicated
accurate target bearing. Later
units of this improved design
were manufactured by local
industry until microwave
equipment was available.

Offers
of New Zealand
Design radars to other
countries

During
1941 before the entry of Japan into WW2
enquiries were made by the
Admiralty in London to ascertain
whether any New Zealand design
equipment could be provided for
use by RN warships based in
Singapore. Although five SW Type
radars and five SG Type were
promised, but later only 24 of
an increased order of the SG
Type were completed. the
first in February 1942. In all
15 were sent to Singapore but
none were delivered for
operational use before the
surrender of Singapore. It is
known that of the nine sent to
Colombo, one on board the NZ
mercantile HAURAKI fell into
Japanese hands when this ship
was intercepted by a Japanese
warship. Seven were sent to
Sydney
later in 1942 to be held as a
reserve for the Eastern Fleet

Microwave
Radar equipment manufactured
in New Zealand

Production
was delayed for many reasons the
principal ones being lack of
experience in waveguide
technology and limited
availability of components such
as magnetrons, spark gaps and
other RF units. Notwithstanding
these difficulties and despite
political problems relating to
the release of complete New
Zealand equipment direct to the
USA; both completed equipment
and personnel to train operators
as well to provide scientific
support supervise of maintenance
and repair, these were provided
and made a significant
contribution to operations
during the US advance towards
the Japanese mainland in
1944-45. The microwave equipment
could either be used a fixed
site or a mobile unit for
warning of the approach of low
flying aircraft and shipping.
Another New Zealandradar
designed for the
RNZAF specifically ordered by
the US Navy for use by Assault
Teams to provide Long Radar
Warning was completely mobile
and consisted of three trucks
containing radar sets,
operational control display
equipment, power supplies and
repair facilities with spares
and documentation.

A
prototype
radar set was produced for
gunnery fire control but the
project was later cancelled.

Radar
Type ME1 (Land Based Warning
Radar.

Land based
outfit microwave radar using
10cm magnetron transmitter and
intended for use on a fixed site
or as a mobile station. The
radiated output varied dependant
upon the design of magnetron
used and provided a two
microsecond pulse with a 500m/c
repetition rate. The associated
super-heterodyne receiver had a
24 M/c with 1M/c Bandwidth. using
a crystal mixer and Sutton Tube
Local oscillator. A
Spark Gap unit (T/R Switch).enabled
use of a single paraboloid,
rotating aerial with waveguide
feed and rotating joints. This
unit was initially mounted on a
rear platform was later
positioned on the rook of the
radar truck. The Display
equipment included 5 CRT (Plan
Position Indicator PPI) for the
first time in a New Zealand
radar and provided a plan view
of the received signal by use of
a rotating time base in
synchroniism with the power
driven aerial. A 5 A Display
was also available with
calibration markers. for
ranging purposes. These items
together with a Plotting Table
for assessment of the current
tactical situation and the
associated command and
communication facilities were housed
the radar truck

A
second truck was used for power
generation equipment using
either petrol or diesel driven
generators, which also contained
suitable repair facilities
including had tools and more
importantly electronic test
equipment produced in New
Zealand. This equipment was
mounted in trays which were
removable and wiring was located
in the upper side with major
components underneath to
facilitate testing and
replacement, This
innovation was available in New
Zealand radars at least 12
months before introduced into RN
designed equipment and ME1
radars were deployed in the
Pacific theatre well in advance
of suitable. US and UK
outfits.

An improved
outfit known as ME1A had a
larger aerial and a higher power
magnetron. The rf
arrangements were improved to
increase accuracy of alignment
of the rotating element and
stability of the transfer of rf
to the aerial. Changes were made
of some receiver components
which had proved to be
under-rated, and two 6KVA diesel
generators used for power supply
in the second truck.

LRAW
Type (Long Range
air Warning)

This
equipment, originally designed
for the RNZAF, was ordered by
the US Navy for use by ARGOS
assault unjts
to provide early warning of
aircraft approach during
deployments in the Pacific. Its
primary significance was that it
was transportable in a Landing
Craft and could be brought into
service more rapidly than the US
270
equipment under combat
conditions. Three
trucks were required for
operational use of LRAW and its
rapidity of operational
availability was increased by
the provision of two aerial
units. Two New Zealand scientists
were used to provide support
during operational use and
served with great distinction to
ensure maximum value of this
type of defence. The first was
deployed operationally in
February 1944 when it was used
during landings on Nissan Islands in the Solomons and
five others were used in later
assault operations.

To obtain long
range warning a lower frequency
of 97 M/c was required and 10
microsecond pulses were
available at 50 cycles per
second with 150-200 KW peak
power for two NT99 output
valves.

A Yagi
type aerial unit was used to set
up the equipment on arrival at
the selected site and was
transported as a demountable
unit during transit and then
fitted to a gearbox on the roof
of the radar truck. The aerial
unit consisted of two separate
arrays with dipole elements used
for transmission and reception.
On arrival at the selected site,
installation on the roof of the
radar truck took less than an
hour and the array could then be
rotated by an electric motor.

A larger
Broadside array was transported
with its mounting tower in
another truck. It comprised 18
dipoles arranged in three stacks
the centre one being used for
transmission and the two outer
stacks for reception. When time
allowed the array was assembled
near the radar truck and was
rotated by an electric motor.
The procedure took less than an
hour.

A
super-heterodyne receiver with
an IF of 24 M/cs
and as bandwidth of 250 K/cs
was used to feed a 9 CRT
display with ranges of 10miles
and 200 miles calibrated at 10
mile intervals. Performance with
the Yagiaerial
was 90 miles on
single aircraft and up to 125
miles on groups. With the
Broadside array these were
100miles at 5,000 feet and over
150 on group at 10,00
feet. Range accuracy was about 1
mile with bearing accuracy of 3
degrees.

US B4 IFF interrogation equipment with New
Zealand
design aerials was fitted with
this outfit in the radar truck
which also incorporated plotting
and communication facilities.

The third truck
contained power supply diesel
generators and support spares
and tools were available with
test gear.

ME4
Plan Position Indicator.

This
New Zealand
design equipment could be used
with RN Type 271 or 272
equipment and provided
two display units. a
9 CRT for local display and a
similar unit to be fitted on
Bridge to provide information
during passage. It is not clear
whether a transmitter and
receiver were produce locally or
the installation was used only
with the RN equipment.
Calibration markers were
available. However after the end
of hostilities this equipment
removed from four RNZN corvettes
and two were was fitted
mercantiles, These
were later modified. by
removal of the existing cheese
type aerial which was replaced
by a 4 feet paraboloid and by
use of a more powerful
magnetron.

New
Zealand
Radar under development in
August 1945

ME5
Plan Position Indicator.

Another
New
Zealand panel for use with CD
units.

Type
ME2 (Fire Control Microwave
Radar Equipment.)

A
prototype New Zealand
design equipment gunnery use was
also developed during WW2 but
this was never put into
production, although the some of
equipment was in use for
development trials for some
months before the project was
cancelled

The aerial unit
included two four foot dishes
with rotating dipoles for
standard 10cm radar transmitters
and the receiver followed the
practice of earlier NZ microwave
equipment but a more
sophisticated ranging system had
been under development which
included an expanded time base
for accurate ranging.

Type
ME3 Microwave Height Finding
Radar

Unlike the ME2
equipment this was designed to
accurately measure height of
targets in conjunction with Long
Range Warning radar such as
LRAW. However the development
programme for this purpose was
cancelled in 1943 and it was not
redesigned unit 1947 was adapted
specifically for use in tracking
of meteorological balloons.

A single
paraboloid aerial unit was used
and the dipole unit could be
moved both in azimuth and
elevation. Originally a 10cm
magnetron was fitted with a
standard super-heterodyne
receiver to provide display
signals on two displays. One of
these was a 5 CRT for range
measurement and the other a 9
CRT t show either Elevation or
Azimuth changes.

To meet the new
meteorological requirements some
major changes were made to the
transmitter and receiver
equipment with more significant
alterations to the display
outfits. This equipment as
modified for used fore several
years.

Conclusions

The
very considerable design and
development work carried out by
the few New Zealand scientists
available,
resulted in many
types of radar equipment being
in operational use in the Far
East before similar equipment,
such as fire control for main
armament of cruisers and
suitable night time costal
defence was available in Europe
or in North America. There work
carried out under severe
restrictions due to lack of
suitable components locally,
without any possibility of mass
production and with no
experience of the new techniques
being used in other countries
was quite remarkable and has
received little recognition in
either the UK or USA. The use of
rack mounted equipment well in
advance of its introduction by
the RN showed a clear
understanding of the very
important need to provide easy
access to equipment for repair
and test as well as to provide
adequate documentation and test
equipment for installation and
support whilst in operational
use. The contribution they made
is worthy of the cause for which
they made so many other
contributions to the allied
victory in 1945